Permutation in String
Difficulty: Medium
Category: DSA
Topics: Hash Table, Two Pointers, String, Sliding Window
Asked at: Facebook, Microsoft, Adobe, Amazon, Yandex
Given two strings `s1` and `s2`, return `true` if `s2` contains a permutation of `s1`, or `false` otherwise.
In other words, return `true` if one of `s1`'s permutations is the substring of `s2`.
**Example 1:**
**Input:** s1 = "ab", s2 = "eidbaooo"
**Output:** true
**Explanation:** s2 contains one permutation of s1 ("ba").
```
**Example 2:**
**Input:** s1 = "ab", s2 = "eidboaoo"
**Output:** false
```
**Constraints:**
- `1 <= s1.length, s2.length <= 104`
- `s1` and `s2` consist of lowercase English letters.